摘要
应用网格距为3 km的中尺度模式MM5v3及3DVAR同化系统,对2006年6月27日夜间发生在北京地区的一次局地强对流天气过程进行了模拟分析。结果表明,模式能够较好地模拟出本次城区西部的局地强降水过程,反映出降水事件的局地性、突发性和短历时特征。分析还表明,直接造成本次暴雨过程的是两个局地生成的中尺度对流系统,地面中尺度辐合线是降水的主要触发机制之一。北京周边陡峭地形的存在,导致山前偏南、偏东气流在迎风坡强烈爬升,并与北面、西面来的过山气流共同作用在山前形成垂直方向次级环流,是强降水维持的主要物理机制。此外,不断发展的城市下垫面亦会对降水过程产生影响。
In this paper, the process of a local and short-time heavy rain in Beijing on June 27th 2006 is numerically simulated by a 3 km-gridpoint-interval MM5v3 model and 3DVAR system. The result of the simulation agrees with the reality. As shown in the research results, two mesoscale convective cloud masses resulted in the rainfall and a surface mesoscale convergence line played the role of a trigger system for the heavy rain. At low levels, the southerly wind converged with the easterly wind and rose on the southern slope of Yan Mountain where cold air brought by the northerly wind also rose slantwise due to the effects of topographic forcing, generating strong vertical ascending motion on the hillside and a secondary vertical circulation on its southern slope. The latter was the main physical mechanism maintaining the heavy precipitation on the mountainous region west of Beijing. Moreover, the effect of urban land use on rainfall also has been analyzed preliminarily.
出处
《热带气象学报》
CSCD
北大核心
2009年第4期442-448,共7页
Journal of Tropical Meteorology
基金
中央级公益性科研院所基本科研业务费专项(IUMKY200705
IUMKY200904)资助
关键词
天气学
暴雨
数值模拟
地形
城市下垫面
影响
synoptic meteorology
heavy rain
numerical simulation
terrain
urban land use
influence
